CH3SiCl3
		Chlorine
	Nuclear Quadrupole Coupling Constants
		in Methyltrichlorosilane
	The component of the Cl nqcc tensor along the threefold symmetry axis in methyltrichlorosilane was determined by Smith [1].  A heavy atom substitution molecular structure was derived by Takeo and Matsumura [2].
	Calculation was made here of the chlorine nqcc's on the substitution structure.  The results are given in Table 1.  Structure parameters are given in Table 2, atomic coordinates in Table 3.
	Coordinate Systems
	Xuu is the component of the nqcc tensor along the threefold symmetry axis.  Corresponding to the atomic coordinates given below in Table 3, Xvv and Xww are the components along the v- and w- axes for the Cl atom in the uv-plane.
	Subscripts x,y,z refer to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the w-axis.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	Table 1.  Chlorine nqcc's in CH3SiCl3 (MHz).  Calculation was made on the heavy atom substitution structure of Takeo and Matsumura [2].  See below.     Calc. Expt. [1]   35Cl Xuu 13.66 13.16(89) Xvv - 32.97 Xww 19.30 Xuv 17.90   Xxx 19.74 Xyy 19.30 Xzz - 39.04 ETA - 0.011 Øz,u 71.24 Øu,SiCl 69.7 Øz,SiCl   1.5
	The pyramid formed by the z-principal axes of the three Cl nqcc tensors is somewhat 'flatter' than the molecular pyramid.  This is typical of the pyramidal trichlorides.
	Table 2.  Methyltrichlorosilane.  Molecular structure parameters (Å and degrees).   rs [2] ropt CSi 1.848 CH 1.090 * SiCl 2.026 SiCH 110.3 ** CSiCl 110.3   * 1.001 × ropt, where ropt = MP2/6-31G(d,p) optimization [3]. ** MP2/6-31G(d,p) optimization.
	Table 3.  Methyltrichlorosilane.  Heavy atom coordinates,  rs/ropt  u (Å)  v (Å)  w (Å) Si 0.3031 0 0 Cl - 0.3998 1.9002 0 Cl - 0.3998 - 0.9501 ± 1.6456 C 2.1511 0 0 H 2.5293 - 1.0223 0 H 2.5293 0.5111 ± 0.8853
	[1] J.G.Smith, J.Mol.Spectrosc. 136,109(1989).
	[2] H.Takeo and C.Matsumura, Bull. Chem. Soc. Japan 50,1633(1977).
	[3] J.Demaison and G.Wlodarczak, Structural Chem. 5,57(1994).
	Related ...
	"An ab initio Study of the Molecular Electric-field Gradients of the Chlorosilanes" H.U.Suter, D.M.Maric, and P.F.Meier, Z.Naturforsch. 51a,41(1996).
	NCl3		SiH3Cl		SiH2Cl2		SiF3Cl
	PCl3		SPCl3		OPCl3		CH3CCl3
	AsCl3		CHCl3		CFCl3		SiHCl3
	Table of Contents
	Molecules/Chlorine
						CH3SiCl3.html
						Last Modified 3 Aug 2006